Our English teacher often stands _____ front of the classroom. [ ]

There is _______ “u” and _______ “f” in the word “unfamiliar”.

. — Why were you so late for work today? — ____ to the office was not very easy this morning because of the traffic.

How do you improve your writing skills?—______ keeping a diary every day.[ ]

This picture was taken a long time ago. I wonder if you can 　　　 my mother.